/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.ui.actions;

import org.eclipse.che.jdt.util.JavaModelUtil;
import org.eclipse.jdt.core.IClassFile;
import org.eclipse.jdt.core.ICodeAssist;
import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.ISourceRange;
import org.eclipse.jdt.core.ISourceReference;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.che.jface.text.ITextSelection;

public class SelectionConverter {

	private static final IJavaElement[] EMPTY_RESULT = new IJavaElement[0];

	private SelectionConverter() {
		// no instance
	}

//	/**
//	 * Converts the selection provided by the given part into a structured selection. The following
//	 * conversion rules are used:
//	 * <ul>
//	 * <li><code>part instanceof JavaEditor</code>: returns a structured selection using code
//	 * resolve to convert the editor's text selection.</li>
//	 * <li><code>part instanceof IWorkbenchPart</code>: returns the part's selection if it is a
//	 * structured selection.</li>
//	 * <li><code>default</code>: returns an empty structured selection.</li>
//	 * </ul>
//	 *
//	 * @param part the part
//	 * @return the selection
//	 * @throws JavaModelException thrown when the type root can not be accessed
//	 */
//	public static IStructuredSelection getStructuredSelection(IWorkbenchPart part) throws JavaModelException {
//		if (part instanceof JavaEditor)
//			return new StructuredSelection(codeResolve((JavaEditor)part));
//		ISelectionProvider provider = part.getSite().getSelectionProvider();
//		if (provider != null) {
//			ISelection selection = provider.getSelection();
//			if (selection instanceof IStructuredSelection)
//				return (IStructuredSelection)selection;
//		}
//		return StructuredSelection.EMPTY;
//	}
//
//
//	/**
//	 * Converts the given structured selection into an array of Java elements.
//	 * An empty array is returned if one of the elements stored in the structured
//	 * selection is not of type <code>IJavaElement</code>
//	 * @param selection the selection
//	 * @return the Java element contained in the selection
//	 */
//	public static IJavaElement[] getElements(IStructuredSelection selection) {
//		if (!selection.isEmpty()) {
//			IJavaElement[] result = new IJavaElement[selection.size()];
//			int i = 0;
//			for (Iterator<?> iter = selection.iterator(); iter.hasNext(); i++) {
//				Object element = iter.next();
//				if (!(element instanceof IJavaElement))
//					return EMPTY_RESULT;
//				result[i] = (IJavaElement)element;
//			}
//			return result;
//		}
//		return EMPTY_RESULT;
//	}
//
//	public static boolean canOperateOn(JavaEditor editor) {
//		if (editor == null)
//			return false;
//		return getInput(editor) != null;
//
//	}
//
//	public static IJavaElement[] codeResolveOrInputForked(JavaEditor editor) throws InvocationTargetException, InterruptedException {
//		ITypeRoot input= getInput(editor);
//		if (input == null)
//			return EMPTY_RESULT;
//
//		ITextSelection selection= (ITextSelection)editor.getSelectionProvider().getSelection();
//		IJavaElement[] result= performForkedCodeResolve(input, selection);
//		if (result.length == 0) {
//			result= new IJavaElement[] {input};
//		}
//		return result;
//	}
//
//	/**
//	 * Perform a code resolve at the current selection of an editor
//	 *
//	 * @param editor the editor
//	 * @return the resolved elements (only from primary working copies)
//	 * @throws JavaModelException when the type root can not be accessed
//	 */
//	public static IJavaElement[] codeResolve(JavaEditor editor) throws JavaModelException {
//		return codeResolve(editor, true);
//	}
//
//	/**
//	 * Perform a code resolve at the current selection of an editor
//	 *
//	 * @param editor the editor
//	 * @param primaryOnly if <code>true</code> only primary working copies will be returned
//	 * @return the resolved elements
//	 * @throws JavaModelException thrown when the type root can not be accessed
//	 * @since 3.2
//	 */
//	public static IJavaElement[] codeResolve(JavaEditor editor, boolean primaryOnly) throws JavaModelException {
//		ITypeRoot input= getInput(editor, primaryOnly);
//		if (input != null)
//			return codeResolve(input, (ITextSelection) editor.getSelectionProvider().getSelection());
//		return EMPTY_RESULT;
//	}
//
//	/**
//	 * Perform a code resolve in a separate thread.
//	 *
//	 * @param editor the editor
//	 * @param primaryOnly if <code>true</code> only primary working copies will be returned
//	 * @return the resolved elements
//	 * @throws InvocationTargetException which wraps any exception or error which occurs while
//	 *             running the runnable
//	 * @throws InterruptedException propagated by the context if the runnable acknowledges
//	 *             cancelation by throwing this exception
//	 * @since 3.2
//	 */
//	public static IJavaElement[] codeResolveForked(JavaEditor editor, boolean primaryOnly) throws InvocationTargetException, InterruptedException {
//		ITypeRoot input= getInput(editor, primaryOnly);
//		if (input != null)
//			return performForkedCodeResolve(input, (ITextSelection) editor.getSelectionProvider().getSelection());
//		return EMPTY_RESULT;
//	}
//
//	/**
//	 * Returns the element surrounding the selection of the given editor.
//	 *
//	 * @param editor the editor
//	 * @return the element surrounding the current selection (only from primary working copies), or <code>null</code> if none
//	 * @throws JavaModelException if the Java type root does not exist or if an exception occurs
//	 *             while accessing its corresponding resource
//	 */
//	public static IJavaElement getElementAtOffset(JavaEditor editor) throws JavaModelException {
//		return getElementAtOffset(editor, true);
//	}
//
//	/**
//	 * Returns the element surrounding the selection of the given editor.
//	 *
//	 * @param editor the editor
//	 * @param primaryOnly if <code>true</code> only primary working copies will be returned
//	 * @return the element surrounding the current selection, or <code>null</code> if none
//	 * @throws JavaModelException if the Java type root does not exist or if an exception occurs
//	 *             while accessing its corresponding resource
//	 * @since 3.2
//	 */
//	public static IJavaElement getElementAtOffset(JavaEditor editor, boolean primaryOnly) throws JavaModelException {
//		ITypeRoot input= getInput(editor, primaryOnly);
//		if (input != null)
//			return getElementAtOffset(input, (ITextSelection) editor.getSelectionProvider().getSelection());
//		return null;
//	}
//
//	public static IType getTypeAtOffset(JavaEditor editor) throws JavaModelException {
//		IJavaElement element= SelectionConverter.getElementAtOffset(editor);
//		IType type= (IType)element.getAncestor(IJavaElement.TYPE);
//		if (type == null) {
//			ICompilationUnit unit= SelectionConverter.getInputAsCompilationUnit(editor);
//			if (unit != null)
//				type= unit.findPrimaryType();
//		}
//		return type;
//	}
//
//	/**
//	 * Returns the input element of the given editor.
//	 *
//	 * @param editor the Java editor
//	 * @return the type root which is the editor input (only primary working copies), or <code>null</code> if none
//	 */
//	public static ITypeRoot getInput(JavaEditor editor) {
//		return getInput(editor, true);
//	}
//
//	/**
//	 * Returns the input element of the given editor.
//	 *
//	 * @param editor the Java editor
//	 * @param primaryOnly if <code>true</code> only primary working copies will be returned
//	 * @return the type root which is the editor input, or <code>null</code> if none
//	 * @since 3.2
//	 */
//	private static ITypeRoot getInput(JavaEditor editor, boolean primaryOnly) {
//		if (editor == null)
//			return null;
//		return EditorUtility.getEditorInputJavaElement(editor, primaryOnly);
//	}
//
//	public static ICompilationUnit getInputAsCompilationUnit(JavaEditor editor) {
//		Object editorInput= SelectionConverter.getInput(editor);
//		if (editorInput instanceof ICompilationUnit)
//			return (ICompilationUnit)editorInput;
//		return null;
//	}
//
//	public static IClassFile getInputAsClassFile(JavaEditor editor) {
//		Object editorInput= SelectionConverter.getInput(editor);
//		if (editorInput instanceof IClassFile)
//			return (IClassFile)editorInput;
//		return null;
//	}
//
//	private static IJavaElement[] performForkedCodeResolve(final ITypeRoot input, final ITextSelection selection) throws InvocationTargetException, InterruptedException {
//		final class CodeResolveRunnable implements IRunnableWithProgress {
//			IJavaElement[] result;
//
//			public void run(IProgressMonitor monitor) throws InvocationTargetException {
//				try {
//					result = codeResolve(input, selection);
//				} catch (JavaModelException e) {
//					throw new InvocationTargetException(e);
//				}
//			}
//		}
//		CodeResolveRunnable runnable = new CodeResolveRunnable();
//		PlatformUI.getWorkbench().getProgressService().busyCursorWhile(runnable);
//		return runnable.result;
//	}

	public static IJavaElement[] codeResolve(IJavaElement input, ITextSelection selection) throws JavaModelException {
		if (input instanceof ICodeAssist) {
			if (input instanceof ICompilationUnit) {
				JavaModelUtil.reconcile((ICompilationUnit)input);
			}
			IJavaElement[] elements = ((ICodeAssist)input).codeSelect(selection.getOffset() + selection.getLength(), 0);
			if (elements.length > 0) {
				return elements;
			}
		}
		return EMPTY_RESULT;
	}

//	public static IJavaElement getElementAtOffset(ITypeRoot input, ITextSelection selection) throws JavaModelException {
//		if (input instanceof ICompilationUnit) {
//			JavaModelUtil.reconcile((ICompilationUnit)input);
//		}
//		IJavaElement ref = input.getElementAt(selection.getOffset());
//		if (ref == null)
//			return input;
//		return ref;
//	}
//
//	public static IJavaElement resolveEnclosingElement(JavaEditor editor, ITextSelection selection) throws JavaModelException {
//		ITypeRoot input = getInput(editor);
//		if (input != null)
//			return resolveEnclosingElement(input, selection);
//		return null;
//	}
//
	public static IJavaElement resolveEnclosingElement(IJavaElement input, ITextSelection selection) throws JavaModelException {
		IJavaElement atOffset = null;
		if (input instanceof ICompilationUnit) {
			ICompilationUnit cunit = (ICompilationUnit)input;
			JavaModelUtil.reconcile(cunit);
			atOffset = cunit.getElementAt(selection.getOffset());
		} else if (input instanceof IClassFile) {
			IClassFile cfile = (IClassFile)input;
			atOffset = cfile.getElementAt(selection.getOffset());
		} else {
			return null;
		}
		if (atOffset == null) {
			return input;
		} else {
			int selectionEnd = selection.getOffset() + selection.getLength();
			IJavaElement result = atOffset;
			if (atOffset instanceof ISourceReference) {
				ISourceRange range = ((ISourceReference)atOffset).getSourceRange();
				while (range.getOffset() + range.getLength() < selectionEnd) {
					result = result.getParent();
					if (!(result instanceof ISourceReference)) {
						result = input;
						break;
					}
					range = ((ISourceReference)result).getSourceRange();
				}
			}
			return result;
		}
	}
//
//	/**
//	 * Shows a dialog for resolving an ambiguous Java element. Utility method that can be called by subclasses.
//	 *
//	 * @param elements the elements to select from
//	 * @param shell the parent shell
//	 * @param title the title of the selection dialog
//	 * @param message the message of the selection dialog
//	 * @return returns the selected element or <code>null</code> if the dialog has been cancelled
//	 */
//	public static IJavaElement selectJavaElement(IJavaElement[] elements, Shell shell, String title, String message) {
//		int nResults = elements.length;
//		if (nResults == 0)
//			return null;
//		if (nResults == 1)
//			return elements[0];
//
//		int flags = JavaElementLabelProvider.SHOW_DEFAULT | JavaElementLabelProvider.SHOW_QUALIFIED | JavaElementLabelProvider.SHOW_ROOT;
//
//		ElementListSelectionDialog dialog = new ElementListSelectionDialog(shell, new JavaElementLabelProvider(flags));
//		dialog.setTitle(title);
//		dialog.setMessage(message);
//		dialog.setElements(elements);
//
//		if (dialog.open() == Window.OK) {
//			return (IJavaElement)dialog.getFirstResult();
//		}
//		return null;
//	}
}
